I am trying to capture a timestamp for when a spreadsheet is first edited, and ONLY keep that first timestamp. However, NOW() updates each time a spreadsheet is edited. I found a working formula (unfortunately only for Excel) which uses circular dependency. Since Google Docs does not support that at the moment, I wanted to find another way around it.
Basically, I want a formula in one cell to paste the timestamp into another cell after checking to make sure the target cell is empty, otherwise just leave as is:
=IF(A2="", A2=Text(Now(), "HH:mm:ss"), A2)
or something like that where this formula would be placed in another cell and would edit A2 only if A2 was empty. Again, if Google Spreadsheet supported circular dependency, I could easily place this into A2 and be done with it. But sadly, I can't. Any help would be greatly appreciated!
Please note, I am trying to accomplish this without scripts, since the number of tabs for this spreadsheet will change dramatically per user. Therefore, I would rather each tab have its own formula to calculate this timestamp.